UK Tax Code Checker
Type any UK tax code — we'll decode it and show what it means for your take-home pay. Supports 1257L, K codes, BR, D0, D1, 0T, NT, Scottish S codes, Welsh C codes and emergency W1/M1 basis.
How UK tax codes work
Your tax code is the four-or-five-character string HMRC sends to your employer to tell them how much Income Tax to deduct from your salary each pay period. Get the wrong code and you'll either pay too much (and have to claim it back) or too little (and get a surprise bill in January).
Every tax code has up to three parts: an optional country prefix, a body that defines your allowance, and an optional emergency suffix.
The numbers
In a standard code like 1257L, the numbers are your personal allowance divided by 10. So 1257 means £12,570 tax-free per year — the standard allowance for 2025/26. 1185 would mean £11,850 (typically because you've transferred part of your allowance to a spouse).
The letters
| Letter | Meaning |
|---|---|
| L | Standard personal allowance — the most common code by far. |
| M | You're receiving 10% of your partner's allowance via Marriage Allowance. Saves £252/year. |
| N | You're giving 10% of your allowance to your partner via Marriage Allowance. |
| T | Your code has special calculations HMRC needs to review — usually the allowance taper above £100,000, or non-standard allowances. |
| 0T | No personal allowance at all. Used when your income exceeds £125,140 (allowance fully tapered) or as an emergency code when HMRC has no information. |
| BR | All income from this source taxed at 20% (basic rate). Common for second jobs. |
| D0 | All income at 40% (higher rate). |
| D1 | All income at 45% (additional rate). |
| NT | No tax. Rare — only for specific exemptions like certain non-residents. |
K codes — when you owe HMRC, not the other way around
A code that starts with K means the opposite of a normal code: instead of tax-free allowance, HMRC is collecting extra tax through your salary. The number after K, multiplied by 10, is the amount being added to your taxable income each year.
Common reasons for a K code:
- You receive the State Pension (which is taxable) alongside a salary.
- You have significant benefits in kind (company car, medical insurance).
- You owe tax from a previous year and HMRC is collecting it through PAYE.
To stop your employer taxing more than half your wages, K codes have a built-in cap: no more than 50% of your gross pay each pay period can be taken in tax.
Country prefixes
If you're a Scottish taxpayer, your code starts with S (e.g. S1257L) — the same allowance but Scottish bands apply. Welsh taxpayers get a C prefix (Cymru). Both are determined by your main residence, not by where you work.
Emergency / non-cumulative codes (W1, M1, X)
If your code ends with W1, M1 or X, you're on emergency basis. Instead of HMRC calculating your tax based on the cumulative year-to-date, each pay period is treated standalone. This usually happens when you start a new job without a P45, or after a major change to your code. It's not a problem — it just means you might overpay slightly until HMRC switches you back to cumulative basis (and refunds any overpayment).
How to find your tax code
- Your payslip. Look near the top — usually labelled "Tax code".
- Your P45 from your previous employer.
- Your P60 at the end of the tax year.
- Your Personal Tax Account on Gov.uk at gov.uk/personal-tax-account.
- The HMRC app (free on iOS and Android).
What to do if your tax code looks wrong
You can change your tax code through HMRC — it isn't your employer who decides it. The fastest route is the HMRC online service (Personal Tax Account) where you can:
- Tell HMRC about a change in income, benefits or job that you think should change your code.
- Claim Marriage Allowance if eligible (£252/year saving).
- Request a refund if you've been on an emergency code and HMRC hasn't moved you back to cumulative.
If you've overpaid by a significant amount, HMRC normally issues a P800 letter at the end of the tax year explaining what you're owed. Refunds usually come automatically by bank transfer or cheque.
Once your code is right, use our take-home pay calculator to see what your monthly net pay should look like — and our guide to reading your UK payslip for everything else on the payslip.
FAQs
What does 1257L mean?
1257L is the standard tax code for 2025/26: £12,570 personal allowance plus the standard L suffix. Most employees in England, Wales and Northern Ireland have this code.
I'm on tax code BR — am I paying too much tax?
Not necessarily. BR means 20% tax on all income from that source with no allowance. It's correct for a second job or pension where you're already using your allowance on your main income. If BR is your only job, that's wrong — your code should normally be 1257L and you should contact HMRC immediately.
Why did my code change to K?
You've started receiving taxable benefits (often a company car or state pension) that exceed your tax-free allowance. The K code lets HMRC collect the extra tax through your salary rather than sending a bill. Check the figures on your HMRC Personal Tax Account — if the benefits listed are wrong, get them corrected and your code will revert.
What's a tax code notice (P2)?
HMRC sends you a P2 "Notice of coding" whenever your code changes mid-year. It breaks down exactly how the code was calculated — allowances minus deductions. Worth reading carefully because mistakes (especially around benefits in kind) are common.
I'm self-employed — do I have a tax code?
Only for any PAYE income (employee jobs alongside self-employment). Pure self-employment income is reported via Self Assessment, not PAYE, so no tax code applies. If you do both, you'll have a code for the PAYE side.